Nowadays, fluid transportation devices used in many sectors such as pharmaceutical industries, computer techniques, printing industries, energy industries are developed toward miniaturization. The fluid transportation devices used in for example micro pumps, micro atomizers, printheads or industrial printers are very important components. Consequently, it is critical to improve the fluid transportation devices.
FIG. 1 is a schematic view of a conventional micro pump. The conventional micro pump 10 principally comprises a valve seat 11, a valve cap 12, a valve membrane 13, a micro actuator 14 and a cover plate 15. The valve membrane 13 includes an inlet valve structure 131 and an outlet valve structure 132. The valve seat 11 comprises an inlet channel 111 and an outlet channel 112. A pressure cavity 123 is formed between the valve cap 12 and the micro actuator 14. The valve membrane 13 is arranged between the valve seat 11 and the valve cap 12.
When a voltage is applied on both electrodes of the micro actuator 14, an electric field is generated. The electric field causes downward deformation of the micro actuator 14. In a case that the micro actuator 14 is subject to upwardly deformation in the direction X, the volume of the pressure cavity 123 is expanded to result in a suction force. Due to the suction force, the inlet valve structure 131 of the valve membrane 13 is opened and thus the fluid is transported into the pressure cavity 123 through the inlet channel 111 of the valve seat 11, the inlet valve structure 131 of the valve membrane 13 and the inlet valve channel 121 of the valve cap 12. On the other hand, if the micro actuator 14 is subject to downward deformation in a direction opposite to the direction X, the volume of the pressure cavity 123 is shrunk to result in an impulse. The impulse is exerted on the inlet valve structure 131 and the outlet valve structure 132 of the valve membrane 13, so that the outlet valve structure 132 is opened. When the outlet valve structure 132 is opened, the fluid is exhausted from the pressure cavity 123 to the outside of the micro pump 10 through the outlet valve channel 122 of the valve cap 12, the outlet valve structure 132 of the valve membrane 13 and the outlet channel 112 of the valve seat 11. Meanwhile, a fluid transporting cycle is completed.
Although the conventional micro pump 10 is effective for transporting a fluid, there are still some drawbacks. For example, the conventional micro pump 10 has a single actuator, a signal pressure cavity, a single flow path, a single inlet/outlet and a single pair of valve structures. For increasing the flow rate of the micro pump 10, an additional coupling mechanism is required to connect multiple micro pump units, which are stacked. Since the use of the coupling mechanism is very costly and the overall volume of multiple micro pump units is very bulky, the final product fails to meet the miniaturization demand.
For increasing the flow rate and reducing the overall volume, there is a need of providing a fluid transportation device having multiple double-chamber actuating structures so as to obviate the drawbacks encountered from the prior art.